Cured films produced by curing a composition formed mainly of an alkali soluble resin that contains polyimide or polybenzoxazole have been widely used as insulating film, protecting film, barrier rib, planarizing film for semiconductor elements and displaying devices, etc. In reflection of the recent increasing demand for high resolution semiconductor elements and display devices, various components including insulating film, protecting film, and planarizing film are now required to have resolutions of several micrometers. To meet these requirements and also realize more simplified production processes, positive type photosensitive resin compositions suitable for fine processing are now widely used. In order to prevent problems such as deterioration, malfunction, and leakage current due to light entering the TFT that drives a display device, furthermore, cured films to be used as insulating layer of an organic EL display or planarizing film provided on the TFT substrate of an organic EL display are required to have a reduced light transmittance particular in the wavelength range of 450 nm or less. When applying a photosensitive resin composition to a display device, for example, there is a call for improving the contrast and solving the problem of visibility deterioration attributed to external light reflection during outdoor use in the case of the insulating layer of an organic EL display or black matrix layer in a liquid crystal display and reducing the light transmittance for visible light in the case of cured film used in the insulating layer or planarize layer.
Techniques for decreasing the light transmittance of a cured film in the visible light region of 400 nm or more include the addition of a coloring agent such as carbon black, organic or inorganic pigments, and dyes to the resin composition as seen in the fields of black matrix material and RGB paste material for liquid crystal displays.
For positive photosensitive resin compositions, techniques available for decreasing the light transmittance of cured film include, for example, adding a quinone diazide compound and a black pigment to an alkali soluble resin formed of a novolac resin and/or vinyl polymer (for example, see Patent document 1), adding a photosensitive agent and a black pigment to soluble polyimide (for example, see Patent document 2), adding a quinone diazide compound and a coloring matter soluble in both the alkaline developer and organic solvent to an alkali-soluble resin (for example, see Patent document 3), adding a black oil-soluble dye to a photosensitive resin (for example, see Patent document 4), and adding an esterified quinone diazide compound and at least one coloring agent selected from the group consisting of dye, inorganic pigment, and organic pigment to an alkali-soluble heat resistant resin (for example, see Patent document 5).